From: Benjamin Poirier <bpoirier@suse.com>
Date: Thu, 18 Jul 2019 10:42:18 +0900
Subject: be2net: Synchronize be_update_queues with dev_watchdog
Patch-mainline: v5.3-rc2
Git-commit: ffd342e087d5c56882c232f6a1812b5e3d89b37b
References: bsc#1127315

As pointed out by Firo Yang, a netdev tx timeout may trigger just before an
ethtool set_channels operation is started. be_tx_timeout(), which dumps
some queue structures, is not written to run concurrently with
be_update_queues(), which frees/allocates those queues structures. Add some
synchronization between the two.

Message-id: <CH2PR18MB31898E033896F9760D36BFF288C90@CH2PR18MB3189.namprd18.prod.outlook.com>
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/ethernet/emulex/benet/be_main.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/drivers/net/ethernet/emulex/benet/be_main.c
@@ -4694,8 +4694,13 @@ int be_update_queues(struct be_adapter *
 	int status;
 
 	if (netif_running(netdev)) {
+		/* be_tx_timeout() must not run concurrently with this
+		 * function, synchronize with an already-running dev_watchdog
+		 */
+		netif_tx_lock_bh(netdev);
 		/* device cannot transmit now, avoid dev_watchdog timeouts */
 		netif_carrier_off(netdev);
+		netif_tx_unlock_bh(netdev);
 
 		be_close(netdev);
 	}